Since the purchase of our laser scanning cytometer (LSC) in 2000, there have been major advances in technology, both in hardware and software for imaging cytometers. CompuCyte has initiated a program whereby LSC users can upgrade their instrument to the newer iCys imaging cytometer. The upgrade takes advantage of using some of the existing parts of the LSC, including the lasers and video camera with monitor, significantly lowering the cost of purchasing a new system. The microscope will be replaced with an inverted Olympus IX-71 microscope. This change allows high throughput scanning in many formats, including microscope slides, chamber slides, microtiter plates, and Petri dishes. In this way, live cells can be viewed in real time, and measurements can be taken at multiple time points in an assay. Some of the other technological advances of the iCys" include autofocus as the instrument scans various parts of a slide or plate, vastly improving scanning time and efficiency, and new automatic data analysis capabilities. CompuCyte is the only manufacturer of these unique analytical cytometers that allow not only for imaging of biological cell and tissue samples, but also sophisticated quantification of many fluorescence and chromatic parameters. Several investigators are interested in being able to analyze biochemical events in live cells, such as induction of apoptosis, changes in redox status, transcription factor translocation, and receptor- mediated endocytosis. Although the LSC allows end point analysis of these events, it is very difficult to capture the actual sequence and timing. The iCys" upgrade will therefore be a very important addition to our state-of-the-art biomedical research equipment on campus. It will complement the existing flow cytometric and confocal microscopy capabilities, allow for novel research applications, and will become the only quantitative imaging research cytometer in Montana. This puts our investigators at the cutting edge of research technologies and helps keep them competitive for major national grant funding on projects that have profound impacts on our understanding of toxicological and pharmacological events, all of which will affect our ability to address many public health issues. As outlined in the proposal, a number of investigators will benefit from this new system, not only in their existing research projects, but also in new questions that they are currently unable to address. In summary, our proposal covers not only an important upgrade of a valuable instrument that is already in use and maintained within an excellent instrument core facility, but adds significantly to its capabilities in addressing critical biomedical research questions.